title of the thesis - Department of Geology - Queen's University

(Fig. 2.12B). Reduction of quartz grain size occurs in shear bands. Within the Fresh Air Raisetype
Shear Zone there is evidence of high strain but little evidence of shearing, though this has
been named a shear zone by mine staff. As a result, sense-of-shear was not determined for the
Fresh Air Raise-Type Shear Zone.
2.3.10 Splays and Minor Shear Zones
The best-exposed splay fault between shears of the 118-System is the Grizzly Shear Zone,
exposed on the 7400 Level (Fig. 2.5). It is a minor shear zone, adjacent to mapped splays and
links the Plum Shear Zone and Fresh Air Raise Shear Zone. The Grizzly Shear Zone strikes
northeast, dips steeply 75° to the southeast and measures approximately 50 cm in width. It has a
well-developed biotite schistosity with biotite mineral lineations that trend to the southwest and
plunge approximately 55°. Near-horizontal crenulations deform the shear zone foliation. The
Grizzly Shear Zone forms a sharp contact with its hosting granite and contains boudinaged wall
rock.
The shear zone is cohesive but a 2-3 mm aperture occurs at the easternmost schist-granite
boundary. This extension may not necessarily represent tectonic extension but rather unclamping
of the confining rock due to the close proximity of the shear zone to an excavation (a drift).
In thin section the Grizzly Shear Zone contains biotite, chlorite and plagioclase with minor
amounts of quartz, calcite and K-feldspar. The shear zone fabric is defined by biotite that weaves
around larger plagioclase grains (Fig. 2.13A). Chlorite found within the Grizzly Shear Zone does
not contribute to the specimen fabric.
Reverse-sense top-to-the-northwest displacement is interpreted from sheared granite boudins (Fig.
2.13B, C), as well as offset granite veins.
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